Candidate. Mabel Caban, MD, is an assistant professor in the Department of Orthopedics and Rehabilitation who will serve as principal investigator of this project. As a research fellow at Baylor College of Medicine in 1999, she initiated studies on disparities in the breast cancer treatment of female patients with disabilities. Dr. Caban seeks to study disability using Medicare beneficiary claims. Career Goals: (1) Develop skills as an independent investigator on health services and outcome research; (2) Develop expertise using SEER Medicare linked database to examine the effect of disability on the diagnosis of breast cancer in older women; (3) Develop public speaking skills and improve scientific communication; and (4) Submit an R01 grant to continue the study of disability and health outcomes. Research Plan. The purpose of the study is to determine the association between disability and tumor size/stage of breast cancer diagnosis. The specific aims of the research are to: (1) Define and validate an algorithm using Medicare claims that identifies women with disabilities (functional limitations). (2) Using the disability algorithm from Aim 1, determine the effect of disability on: (a) The use of screening mammography using SEER Medicare linked database. (b) Tumor size and stage at diagnosis of breast cancer using the SEER Medicare linked database. (c) Tumor size and stage at diagnosis for different subpopulations defined by age at diagnosis, race/ethnicity, and socio-economic status using the SEER Medicare linked database. (3) Build two multivariable models (to predict size and stage) to determine the effect of disability on tumor size and stage adjusting for other relevant confounders using the SEER Medicare database. I will apply the algorithm from Aim 1. Method. The disability algorithm will be developed using Medicare Current Beneficiary Survey. The algorithm will then be applied using SEER Medicare linked database to study all breast cancer cases in women aged 69 and older who are in the SEER registries from 1995 through 1999 to determine the effect of disability on use of mammography and on tumor stage/size. First, the analysis will be unadjusted, then stratified by subgroups (age, race, stage), and then adjusted by relevant confounders in a multivariate model.